Spark-plug.



'5e that the same may be renewed without the Lemans.'

' MAURICE r. SULLIVAN, or NEW YORK, N. Y. f

SPARK-PLUG.

To ill lwhom it may concern: Be it known that I, MAURICE l?. SULLIVAN, a. citizen of the United States, residing at .N egrqYork, in the county and State of New Yorkfhave invented certain new and useful Improvements in Spark-Plugs, of which the following is a speciication.

- My, invention relates to sparking means used in connection with internal combustion engines, and in particular it has to do -with that class in which electric sparks are A employed to ignite the explosive vmixtures in the engine cylinders. l

Owing to the severe workingconditions which spark plugs are called upon' to withstand, such as the intense heat and Lpressure of the exploding gases, the destructive yaction.

ofoils and combustion products, and the wearing action of the electric sparks, it is the case that ordinary plugs of the present day v practicev cannot be relied upon to give satisfactory service for any` great length ofl time.

This fact is especial y evident when. it isy taken into lconsideration that the electrical requirements are such as to dictate the use of a certain class of materials for insulation purposes, all of which materials are mej chanically, by far inferior and less durable than the other parts of the plug. The inevitable result is that after a time the weaker "portions are liable to become impaired or damaged, therebyT rendering the'whole de'l vice ineffective'.

It is one of the main ob]ects"!of my lnvention 'to construct a plug in which the liability of dama'geis comparatively small,

and at thesame time to provide means for replacin the less durable arts of the plug as they ecome worn or roken. By this provision :mold plug may be easily and quickly rendered substantially as good as new, and at a relatively low cost.

' Another object is to construct the central kelectrode assembly so that the terminal thereof may be removed and a new one substituted in its place without removing the shell portion from its working position in the engine cylinder.

It is also another object to provide a plug in which the ground terminal is so arranged I. "necessityof detaching the shell from. the enof which are hereinafter described and `partlcularly pointed out in the appended claims.

In the accompanying drawing Figure 1` 1s a view, partly in section, showing a spark l60 plugin which the features of my invention are embodied.

Fig. 2 is a view, partly in section, and

on an enlarged scale, Iillustrating the replaceable portion yof the plug.

4F ig. 3' is a view si ilar in nature to'- l, yet showing a modied form of construcj .y

tion. y y With particular reference tothe drawing,

wherein like characters designate like arts 7,0A

in the respective views, 1 is the shell or odymember of the plug having an.'externalk-il thread 2f and shoulder 3, a suitable gasket i ,usually being used below'shoulder-f-which permit said plug to be applied to,.the:cylin" der of an engine with the assurance vof a tight joint. A gland 4 carries '3.1Srewr-- thread 5 adapted to "engage jan, .internal thread in theupper portion of the shell-` Extending through a centrally disposedbore in gland 4: is the u per portlon of the. central electrode 6, thls electrode has.a'-thread- 7 turned on itsupper end while at its lower end, as at 6,it is of somewhatlarger diam-V eter. Said upper portion of the central lelectrode may be of any suitable conducting` material and carriesa core 8 of insulation, such as mica or the like. wrapped rmly aboutthe electrode `6 andis of such diameter as to provide a press-fit when assembled in position within'v the gland 4. An insulating jacket 9 f'porcelain or other suitable material lits-,on over the screw.

thread 7 and is held in place by a threaded cap 10.v In the lower end lof electrode 6 95 there is a concentric recess-11 the-purpose l of which is hereinafter explained.. p

The lshell 1 is of hollow formation having, as hereinbefore stated, an internal threadl at its upper end. The'lower ed of the shell '10o is provided with a smooth circular bore. ofv

a `diameter somewhatless than'th'at of said i threaded portion. Atthejunctipn of said threaded and smooth-portions. of the 'bone Y of shell 1 there is formed a beveledl annular 105 shoulder 12. Coperati'ng with the upper portion of the central electrode l6 is a supplemental or `lower portion. 13 in the form of "a spindle, having atV one vvend a circular 'rhe com `e is disky l14 and an enlarged pirojectingpoint 15, 11(1) said disk 14 vand projecting poi-nt 15; being, .ifv desirable, constructed integral withh the' e.;-

l .fWith'these and other4 objects inviewfimy invention yfurther .contemplates certain novel j; 'featursef construction' andfoperatiomzall tions imposed upon the terminal points of.

spark plug electrodes.

(desirable.

Referring now to Fig. 2, in which the essential features of my invention are embodied, 16 is a cylindrical shell or cartridge having at its upper end a beveled flange 17 Within this .cartridge and engaging the same with a tight it is a core of insulating material 18, preferably of porcelain, of hollow construction, and having a, shoulder 19 intermediate of its ends provided with a central hole of a diameter suflicient to accommodate the spindle 13 with a snug fit, yet permitting thevsame to be removed if 14 seats against shoulder 19 holding spindle sparkgap.

'13 in proper position.A In the bottom of core 18 is an. annular groove adapted to accommodate the annular ring 20. Ring 20, which is of suitable material, carries the ground e ectrode terminal 21, and is held in place by a flange 22 of the cartridge 16.

The construction shown in Fig. 2 is a unitary structure in itself and vis replaceable with respect to the plug proper. When assembled, the cartridge 16 of said unitary structure slides into the' previously mentioned bore in shell 1, the shoulder-17 engaging the beveled shoulder 12 of said shell. The gland 4 also has a beveled shoulder 23 'which, when `said gland is adjusted in position, engages shoulder 17presses the same firmly against shoulder 12 and thereby insures a tig t joint. As thel gland 4 is screwed in ace the concentric recess 11 in the bottom of electrode `6 passes on over and around the projecting. point 15. A slight gap is retained between the bottom of the recess and the end of said point in order that Shoulders 23, 17 and 12 may seat against one another properly. The spacing between the side walls of recess 11 and the point 15' is however, so slight that the current in traversing'the central electrode readily passes from member 6 to point 15 and thence-to the In the modification as shown in Fig. 3 I have made the recess 11 inthe end of member' 6 Somewhat deeper, and provided the same with an inte al screw-thread. The

point -15 also carries a' thread which engages said internal thread to hold the disk ;f e with a proper engagement between` 65 s oulders 23, 17 and V12.

When thus assembled the disk According to my invention I have pli-ovided a construction in which the less ,durable parts of the plug, such as the. insulating core 18, ground electrode terminall 21, and central electrode terminal 13 are all brought together in a simple compact unitary structure, and which may be readily detached as a unitary structure from the remainder of the plug without removing ihe shell 1 from its position in the engine cy inder for the purpose of inspection or Ithe substitution of new parts, and whensaid new unitary structure is installed inthe old shell the advantage of a new gasket ,engaging surface is thereby obtained. A plug embodyn these features of construction makes inspection and replacement of parts a very simple matter, since it is not necessary to disturb the shell or body member. This is accomplished as hereinbefore described by giving to thehollow shell 1 an internal diameter at its upper end sufficient to allow the cartridge 16 and its associated parts to be inserted within or extracted from its working position in said shell 1. In practice this shell, owing to moisture and other conditions, is liable to become rusted into the engine cylinder with the result that considerable diiiculty is experienced in removing the same, which removal is often necessary for inspection and repair Where the ordinary construction is used. In case the central electrode terminal alone becomes worn or damaged it may be replaced by-*a new one without necessitating the change of any other parts of the' plug.

Another characteristic of the replaceable unitary structure is the manner'in which the porcelain core -18 is inclosed by the metal cartridge 16. In ordinary porcelain plugs the porcelain insulation is openly exposed on all sides to the heat and concussion of the engine gases, and owing to the brittle nature of this material serious trouble is often encountered. In my constructiony the cartridge 16serves as a protecting housing which aids materially in relieving the porcelain insulator from these dangerous pressure conditions.

.Obviously many changes and alterations may be made 4in the construction shown and I do not care to limit myself to the exact.y

details shown therein.

Having thus described my invention what -v I claim is: v

1. In an electrical spark plug, a body so f tar structure including ai' metallic cartri ge, a ground electrode terminal, an insulating core anda supplemental portion of nemica lsaid central electrode including the terminal thereof being supported by said core and detachable therefrom without removing said body from the engine cylinder.

2. In an electrical spark plug, a body mem- 'ber adapted to be attached to the cylinder of a, gas engine or the like; a gland supported by said body member; a portion of 4central electrode including the lterminal.

thereof being supportedl by said core and'detachable therefrom without removing said body from the engine cylinder.

3. In an electrical spark plug, a hollow shell adapted to be attached to the cylinder of a gas engine or the like, said hollow shell having an enlarged internal diameter at its upper end with threads thereon, a unitary structure including; a metallic cartridge having its upper end liared'to fit within said enlarged diameter and a ground electrode attached to the other end thereof, an insulating core within said cartridge, a cen-v tral electrode terminal carried by said core adapted to coperatewith the said groundl electrode; .a second insulator carrying a portion of a central electrode, a gland adapted to be press-fitted onto said second electrode and having threads to engage threads on the enlarged part of said shell and to'urther engage the ilaredportion of saidcar-v tridge to hold the same securely in place within the shell and provide a gas-tight joint, with means for connecting said central electrode portions in operative relationship. A

4. In an electrical spark plug the combination of a body member, a glandsupported thereby, central and ground electrodes, Asaid central electrode consisting of an upper and a lower portion the upper portion having ai recess in its end and being secured within V.said gland but insulated therefrom, the lower portion of said central electrode having av disk near one end and a projectingl point thereabove, a metallic cartridge having a flange at one end,.a hollow insulating member contained within said cartridge, a brid ing portion within the insulating member aving an aperture therein adapted to receive the lower portion of the central electrode, said metallic cartridge being "so arranged within the body member that theI projecting point on the lower portion of the.

central electrode is inclosed by said recess,

the disk thereon serving a guide to hold the same in position, and means carried by the gland and body member to cooperate with the flange on said cartridge for the purpose of providing a vtight joint.

5. In an electrical spark plug the combination of a body member of hollow formation with a beveledyshoulder intermediate of its ends, a gland supported by the body member and having a beveled shoulder at one end thereof; a portion .if a central electrode with a recess in the end thereofgsaid portion being supported by and insulated from said gland; a unitary structure comprising a metallic cartridge having a flange at one end, a hollow insulating core supported within said lcartridge and having an internal shoulder, a supplemental portion of said central electrode provided with a projecting point at its upper end and being detachably supported within said insulating core by said internal shoulder, and `the terminal of a ground electrode;1said unitary structure being detachably arranged withinv thebody member in such a way that the iiange of said cartridge cooperates with the beveled'shoulders 'of the .gland and body' member to provide a tight joint; said projecting point of the supplemental portion being adapted to cooperate with said recess to complete the'centralelectrode.

6. In lan electrical spark plug the combination of a body member having an internal beveled shoulder, a gland havingv abeveled shoulder and supported by said body member, a central electrode comprising two. parts one of which has a recess in its lower.

end and is arranged within said gland but i i insulated therefrom, a cartridge Ahavi'ng a flange at one end, a hollow insulating'member secured within said cartridge with an internal shoulder thereon, the second part.

of said central electrode being supported by said internal shoulder and. having` an enlarged projecting point which cooperates*v with the recess in the' iirstsaid part of the fiange on said cartridge and the beveled shoulders of the gland and body member are minal, said cartridge, -insulating member.

ground electrode, and the second part of said central electrode comprising a single unitary structure which is detachably supported within the body member of the plug.

' MAURICE r. SULLIVAN. y 1 l 'cpres ei this patent may be obtained for ve cents each, by addressing the Commissioner et Patents,

Washington, D. C.

105 central electrode in such a way that the f In V-witnesswher-eof'l aiixmylsignature. l 

